156 GENERAL SYSTEMATIC BACTERIOLOGY 



multiply for a time in the laboratory. He concluded that the organ- 

 ism is most closely related to the bacteria, but that it constitutes a very 

 distinct type. 



It would appear that the genus Achromatium Schewiakoff is valid, 

 with the type species A . oxaliferum Schewiakoff, It is listed by Smith 

 (1905, p. 174) as a doubtful bacterial genus and in another list as a 

 rejected name. Migula (1904, p. 128) states that he appends the 

 genus Achromatium to the bacteria, although (because of the cell 

 dimensions) he considers the relationship distant. A careful rechecking 

 of the work of Schewiakoff on the question of the composition of the 

 granules would be helpful in determining the affinities of this organism. 



Buchanan (1918, p. 462) included this genus as the type of the familj'- 

 Achromatiaceae with the following description: 



Cells large, nearly spherical in newly divided cells to ellipsoidal, 15 to 43 by 

 9 to 22/i. Cells closely packed with large granules, at first interpreted as sul- 

 phur, but later interpreted as calcium oxalate. When granules are dissolved, 

 cells show coarse alveolar structure. Cells are motile, flagella not demon- 

 strated. Cell division resembles the constriction of flagellates rather than the 

 fission characteristic of bacteria. 



This generic diagnosis was also used by Bergey et al. (1923, p. 410). 



In this treatise Achromatium is accepted as a valid bacterial genus. 



Achromobacter. A generic name proposed by Bergey et al. (Com- 

 mittee Soc. Am. Bact., 1923, p. 132) for the single genus of the tribe 

 Achromobacter eae. The generic description is: 



Non-pigment forming (at most no pigment formed on agar or gelatin) rods, 

 occurring in water and soil. Motile or non-motile. Gram-negative. 

 The type species is Achromobacter Liquefaciens (Frankland). 



In all some 51 species are included in the genus. 

 Achromobactereae. A name used by Bergey et al. (1923, p. 132) for 

 the second tribe of the famil}^ Bacteriaceae. The tribal description is: 



Rods, small to medium in size, occurring principally in water and soil. Form 

 no pigment on agar or gelatin but may produce a brownish growth on potato. 

 Cultural characters variable. Motile or non-motile. Gram-negative. 



One genus only is included, Achromobacter. 



Acidobacteriaceae. The first family of the order Peritrichinae of 

 Orla-Jensen (1909, p. 343). It includes seven genera: Denitrobacterium, 

 Bacterium, Propionibacterium, Caseobacterium, Streptococcus, Micro- 

 coccus and Sarcina. It includes organisms which usually cause acid 



